In my copending application Ser. No. 114,032, filed Jan. 21, 1980, now U.S. Pat. No. 4,322,011, there is disclosed and claimed a plastic closure for sealing a container of pressurized fluid wherein the closure has a panel and integral skirt defining internal threads cooperating with the threads of the container and an annular side sealing rib extending inwardly from the inside surface of the skirt above the threads and dimensioned to form an interference fit with an external cylindrical sealing wall of the container and a flexible annular wall integrally connecting the periphery of the panel and the side sealing rib.
Among the objectives of the present invention are to provide an improved package of this type which will accommodate for tolerances in the manufacture of the closure and container.
In accordance with the invention, the container neck has an external frustoconical sealing surface formed above the threads and extending upwardly and radially inwardly, and the molded plastic closure has an integral annular side sealing rib extending radially inwardly from the inner surface of said skirt and engageable with the external frustoconical sealing surface of the container in an interference fit such that when the closure is threaded on the container, the rib is compressed into sealing relation with the external frustoconical sealing surface and a flexible annular wall integrally connecting the periphery of the panel and the sealing rib flexes.